Bacteria

(bak-te’-re-a). A group of very small vegetable organisms, consisting of single cells which multiply by transverse division. They obtain nutriment from dead organic matter which they decompose, and are the causes of fermentation and putrefaction. Those which are in the form of short rods or ovoids are generally called bacilli, those which are minute spheres are called cocci, and those which are more or le spiral or corkscrew-like in shape are called spirilla. There are many species, of which a few cause disease in man or animals, and are therefore called pathogenic. The most important of these now known, are the bacillus of anthrax, the bacillus of tuberculosis, the bacillus of diphtheria, the bacillus of typhoid fever, the spirillum of Asiatic cholera, the bacillus of influenza, the bacillus of plague, and the various forms of cocci which produce inflammation, suppuration, erysipelas, septicæmia, pneumonia, gonorrhœa, .